The present invention relates to improved locking sleeve assembly for use on a knock-down display shelf which is made up of four supporting pillars, multiple inner locking sleeves, rest boards, a top board and a plurality of retaining caps. Each locking sleeve assembly is made up of a separable inner locking sleeve and a retaining cap which has a roundly flanged bottom and a hollow central tubular portion provided with a tapered inner surface. On the circular flange of each retaining caps are disposed a number of counter sunk screw holes. At each corner of a rest board is disposed a counter sunk through hole in which a bottom-flanged retaining cap can be placed and fixed in place by screws engaged with the screw holes on the circular flange. Each supporting pillar has a plurality of equally spaced ring grooves so as to permit halves of the separable locking sleeves, each having a peripherally extended rib on the inner surface, to be selectively engaged with the grooves of a supporting pillar at various levels. Each retaining cap has a number of axial splits on the vertical wall of its hollow central portion for permitting the retaining cap to be flexibly operated when dismantled. In assembly, the locking sleeves are engaged with the 4 supporting pillars at different levels with every 4 sleeves located at the same level, then a rest board is engaged with the 4 supporting pillars with the counter sunk through holes, each having a retaining cap engaged therewith, of the rest board guided through the 4 supporting pillars. The tapered retaining caps can firmly and tightly engaged with the locking sleeves so as to support rest boards in place. To dismantle the display shelf, the splitted retaining caps are easily disengaged with the locking sleeves along with the rest boards.
Referring to FIGS. 1, 1A, 2, 2A, a conventional display shelf is made up of 4 supporting pillars 10, a plurality of locking sleeves 20 rest boards 30 and a top board 40. Each supporting pillar 10 is provided with a plurality of equally spaced ring grooves 11 and a soft pad 12 at the bottom end thereof. Each locking sleeve 20 is made up of two semi-tubular halves 21 each of which has an engagement recess 211 on an axial edge and a protruded lug 212 on the other axial edge so that two semi-tubular halves 21 can be bound together to form a tubular locking sleeve. Each half has a laterally extended rib 213 on the inner surface thereof which can be selectively engaged with a ring groove 11.
Each rest board 30 has a tapered through hole 31 at each corner thereof. The top board 40 has a round cavity 41 at each corner on its underside.
As shown in FIGS. 2, 2A, the assembly of such a display shelf is easily done by first mounting 4 locking sleeves 20 onto the 4 supporting pillars 10 at the same level. Two halves 21 of 4 locking sleeves 20 each having a curved lateral rib 213 on the inner face thereof are engaged with the supporting pillar 10 by way of the ring groove 11 at a selective level. Every two halves 21 of the locking sleeves 20 are interlocked together firmly by way of their corresponding recesses 211 and the protruded lugs 212 that are integrally engaged with each other after they are engaged with the selected ring groove 11 in assembly. Afterwards, the rest boards 30 are consecutively engaged with the supporting pillars 10 with the tapered through holes 31 in locking engagement with the locking sleeves 20, and the top board 40 is attached to the top end of the respective supporting pillars 40 by way of cavities 41 at the corners thereof.
Such conventional locking sleeves assembly used in a knock-down display shelf has a following disadvantage in practical use. Each tapered through holes 31 at the corners of a rest board 30 is in tight engagement with a locking sleeve 20 to avoid loose assembly of a display shelf. However, when the rest boards 30 are adjusted of the distances thereof, the tight engagement of the locking sleeves 20 and the tapered through holes 31, as shown in FIG. 2A, makes the disassembly of the display shelf difficult.